In addition to Kindred 109, Kindreds 133 (cancer family syndrome), 134 (Gardner syndrome), 267 (multiple polyposis coli), and 268 (Gardner syndrome) are now updated and available for systematic studies. These kindreds will be monitored clinically, and skin, blood, colonic lavage, intestinal biopsies, and other specimens will be obtained as warranted for investigation of polyp development, CEA measurement, tritiated thymidine incorporation for cell kinetics studies, karyotype analysis, cytoskeleton comparisons, virus interaction and transformation of fibroblasts, and biochemical studies of collagen and enzymes in relation with familial colorectal polyposis and the Gardner syndrome. Clinical extent and severity of the fibrous displastic problem associated with desmoids and mesenteric fibromatosis will be further defined as a part of this study. This information will be correlated with biochemical and electron microscopic collagen studies.